Engine Hesitates at 1500-1800 RPM under Load

I have a 91 Honda Accord LX. The engine hesitates when under load at 1500-1800 RPM. I've read thru the forums that it could be caused by the EGR ports being plugged up.
I disconnected the vacumm line from the EGR valve and the hesitation stopped.
The EGR valve sits on the intake manifold runners and it looks like the EGR ports come off the top of the runners; but all the plugs in the top of the runners are fixed permanent type (non-removable). What do I have to do to clean them out?

Thanks.

OK, I did a little research. Found a website that has good instructions on what to do. Here is the link if anyone else has a similar situation.

http://autorepair.about.com/library/faqs/bl053c.htm